My first question, is this casual curiosity, a quick fling or are you really serious about your friend's sister as potential LTR material.

Never done it myself, suggestion, first find out if she's interested, two ever so carefully approach with tact and be up front, I'm interested in your sister. Now if you have a reputation of being the group player, you have no chance in hell.

Are you really that desperate? Sounds like you only want the pussy and nothing more. If that's the case why mess with your boy's sister? Plenty of hoes out there that won't potentially destroy a friendship.

I did not get the feeling that he was desperate, but maybe I am wrong. But I sincerely believe that people should have the right to love, that is if he is talking about love in this case of course, who ever they want to or whoever their heart falls for. No matter whose sister she is.

If you like the gal, then i would say follow your heart. But if this is just about sex and pussy, then please just let tell you dick you will let this one pass. And don't put your friendship in jeopardy.

I have done this. It worked out fine with about 6 months of awkwardness after the breakup. Stronger friendship with my buddy for it.

Are you guys like real close now
I cant imagine how hard it would be to stand next to a guy who was your friend but banged your sister and than broke up with her, there would be alot and definitely no also alot and oh and